linux-kernel - Re: [PATCH] clk: Remove global clk traversal on fetch parent index

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Message-ID: <154835742949.136743.9149540159914235850@swboyd.mtv.corp.google.com>
Date:   Thu, 24 Jan 2019 11:17:09 -0800
From:   Stephen Boyd <sboyd@...nel.org>
To:     Derek Basehore <dbasehore@...omium.org>, mturquette@...libre.com
Cc:     linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        Derek Basehore <dbasehore@...omium.org>
Subject: Re: [PATCH] clk: Remove global clk traversal on fetch parent index

Quoting Derek Basehore (2018-12-20 16:31:00)
> It's not required to traverse the entire clk tree when the parents
> array contains a NULL value. You already have the parent clk_core
> pointer, so you can just compare the parent->name and parent_names[i]
> pointers.
> 
> In cases where clk names are never registered, this can be
> a substantial power improvement since a mux having an unregistered
> parent name will traverse the clk tree on every set_rate. This can
> happen hundreds of times a second on CPU clks.
> 
> Change-Id: I85499d2e576249568ff508e424ca8d5009e6e2b1
> Signed-off-by: Derek Basehore <dbasehore@...omium.org>
> ---

Applied to clk-fixes + some commit text and comment updates.